File:ObservatorySydney1874.jpg|thumb|250px|The observatory photographed in 1874
File:SydneyObservatory1 gobeirne.jpg|thumb|250px|The observatory today
'''Sydney Observatory''' is located on a hill now known as Observatory Park, Sydney|Observatory Hill
in the centre of Sydney
The site evolved from a fort built on 'Windmill Hill' in the early 19th century to an Astronomy|astronomical observatory
during the nineteenth century. It is now a working museum where evening visitors can observe the stars and planets through a modern 40 cm Schmidt-Cassegrain telescope
and a historic 29 cm refractor telescope
built in 1874, the oldest telescope in Australia in regular use.